Summary of Aix storage management

restudy old materials ：   

         Do you know how to calculate the size of the logical volume in the actual physical hard disk ？ Through the previous explanation , It is not difficult to know that logical volumes are composed of logical partitions , So just know how many logical partitions there are . Is that right ？？？ This statement is half right , The reason is that a logical partition can map one to three physical partitions .

        1、 If the logical volume has no copies （ Namely Lv Its own size ）

         The size of the logical volume in the actual physical hard disk （MB）=PP Size （MB）×LV contain LP The number of

         2、 If the logical volume has a copy

         The size of the logical volume in the actual physical hard disk （MB）= PP Size （MB）×LV contain LP Count （ individual ）×LV Number of copies

         Link to the original text ：​ ​AIX Create logical volumes for storage management and view and modify attributes ​​

know sth. new ：

        Today I want to talk about the above AIX A summary of storage management , Mainly some fragmented knowledge points , If you are interested, you can have a look .

        （1） Logical volume manager （Logical Volume Manager, Shorthand for LVM） Is a set of operating system commands used to establish and control logical volume storage 、 Library functions and other tools .
        （2）LVM The components of are ∶ Physical volume （Physical Volume）、 The volume group （Volume Group）、 Logic volume （Logical Volume）、 Physical zoning （Physical Partition）、 A logical partition （Logical Partition）、 file system （File System） etc. .
        （3） disk Ouorum It is normally accessible in a volume group VGDA and VGSA Of the volume group VGDA Total sum VGSA Ratio of total . Generally, available VGDA/VGSA achieve 51% Or more , Volume group can be activated .
        （4） Logical volume mirroring is to save the data on each logical partition in the logical volume to 1～3 On physical partitions , That is, each logical partition has 1～3 Copies . If there's only one copy , Then the logical volume has no mirror ; If there is 2 or 3 Copies , Then the logical volume has a mirror , That is, a logical partition mapping 2 or 3 Physical zones .
        （5） Depending on the location of the logical volume on the hard disk , The section of the hard disk can be divided into 5 Concentric regions ∶ Outer edge （Outer-Edge）、 Outer middle （Outer-Middle）、 The central （Center）、 In the middle （Inner-Middle） And inner edge （Inner-Edge）. In the central area I/O Best efficiency , Best performance .
        （6） To display information about physical volumes , Just use Isdev -Cc  disk or lspv command ; use chdev -l hdiskname -a pv=yes The command can configure a hard disk as a physical volume ; To delete a physical volume, use rmdev -l hdiskname -d command ;
        （7） use mkvg Command to create a new volume group ; use lsvg The command displays volume group information ; use chvg Command to modify the properties of a volume group ; use extendvg Command to add a new physical volume to a volume group ; use reducevg The command deletes a physical volume from a volume group ; use varyonvg Command activates a volume group , use varoffvg Command deactivates a volume group ;
        （8） The logical volume control block holds important information about the logical volume , It is located at the beginning of the logical volume , Occupied 512 Bytes . The logical volume control block includes ∶ Logical volume creation date 、 Number of mirrored copies of logical volumes and file system mount points . use /usr/sbin/getlvcb The command can obtain the LVCB Information .
        （9） The strategies that have the greatest impact on the performance of logical volumes are ∶Intra-Disk Allocation（ Internal allocation of disk ）、Inter-Disk Allocation（ Allocation between disks ）、I/O Scheduling（I/O Operation scheduling ） and Write-Verify（ Write check ）.
        （10） Inside the disk （Intra-Disk） The allocation policy determines the actual physical location of the physical partition of the logical volume on the disk ; Between disks （Inter-Disk） The allocation policy determines the distribution of physical partitions of a logical volume among multiple physical volumes , It mainly includes the scope of physical partition distribution （Range） And strict （Strict） Degree of .

        （11） use lsvg or lslv The command displays information about logical volumes ; use mklv Command to create a logical volume ; use rmlv Command to delete a logical volume ; use chly Command to modify the properties of the logical volume ; use extendly Command to increase the size of the logical volume ; use cplv The command copies a logical volume to a new logical partition or an existing logical partition .

Let's talk about storage management for now , The next article brings you 《​ ​AIX Overview of file system ​​》